Ever seen a period movie where the heroine coughs droplets of blood into a hanky? You've witnessed a re-enactment of the disease that was a leading cause of death in the U.S. and Europe in the late 1800s and early 1900s [source: NIH]. Back in 1892, tuberculosis (TB) was responsible for one out of seven deaths in the U.S. [source: Haynes].

Also known as consumption, TB spreads when a person infected with Mycobacterium tuberculosis coughs, sneezes or otherwise transmits droplets through the air to someone else [source: CDC]. Roughly a third of the global population is infected with latent TB, which yields no symptoms and is not contagious in that stage, but probably will be in time [source: WHO]. Once it evolves into TB disease, the bacteria usually wages war on the lungs; hence the notoriously bloody cough, as well as chills, night sweats and fever.

Antibiotics and upgraded living conditions have significantly contributed to the decline of TB in modernized countries. Unfortunately, it continues to plague developing countries, with roughly 95 percent of TB diagnoses and deaths situated squarely in their borders. However, treatment and containment efforts are making a dent; the worldwide death rate from TB dropped 45 percent between 1990 and 2012. Nevertheless, multi-drug resistant TB is at very high levels [source: WHO].